Dealers of alternative fuel vehicles, and especially trucks motoring from fuels such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG), conduct service on these vehicles when required to fulfill warranty obligations. In order to safely service the engine the fuel should be purged from the fuel system, which normally involves defueling by transferring to another tank or venting. Depending on the length of the repair or the amount of fuel available it may not be practical or possible to reuse the fuel as it evaporates over time. After servicing is completed the trucks must be refuelled (with LNG or LPG) before being returned to the operator. Service locations are normally not equipped with an LNG/LPG fuelling station due to the economic costs and operating license requirements associated with such a facility. Instead, dealers have employed a number of alternative strategies to refuel trucks after servicing.
In certain situations it is possible that LNG/LPG can be transferred from the fuel tank of the truck to a secondary storage vessel before servicing begins, and then after repairs are completed the LNG/LPG can be transferred back to the truck. This method requires specialized equipment to perform the transfer, and typically involves substantial venting and waste of fuel to the atmosphere. Another approach that obviates the need for specialized equipment involves transporting LNG/LPG to the service location such that the truck can be refuelled by a mobile refuelling facility. The operator of the mobile refuelling facility requires a permit to transport LNG/LPG fuel which increases the cost of repair. There is also an inconvenience associated with waiting for the mobile refuelling facility to arrive at the service location.
Another solution involves CNG or LNG cylinders that are strapped onto the truck in a temporary arrangement. The cylinder strap-on arrangements are typically in locations that do not comply with vehicle installation codes related to regulations governing fuel tanks. Cylinders containing LNG are most commonly employed in this regard, and using these cylinders results in excessive fuel wastage from venting to atmosphere. Due to the disadvantages associated with the above methods, trucks are normally refuelled by towing them to a fuelling station. This solution does not require licensing or permits, and does not involve expensive specialized equipment. However, the cost associated with towing can be considerable which increases the warranty cost to dealers that ultimately leads to greater costs for truck operators as well.
The present method and apparatus refuel a vehicle after servicing without significantly wasting fuel through venting and without incurring a significant economic cost.